


changes

by MoreThanSlightly (cadignan), verity



Category: Voltron: Legendary Defender
Genre: Alien Biology, Anal Fingering, Anal Sex, Galra Keith (Voltron), Galra Puberty, Gender-Neutral Pronouns for Pidge | Katie Holt, Hunk (Voltron) is a Good Friend, Keith (Voltron) has a vagina for part of this fic and a penis for the rest of it, Knotting, Krolia (Voltron) is a Good Parent, Lust, M/M, Masturbation, Mating Cycles/In Heat, Mother-Son Relationship, Oral Sex, Penis In Vagina Sex, Pidge (Voltron) is a Good Friend, Porn with Feelings, Puberty, Sex Talk, Sex Toys, Shiro (Voltron) is a Good Boyfriend, Sparring, Switching, Vaginal Fingering, vaginas
Language: English
Status: Completed
Published: 2018-12-31
Updated: 2019-01-01
Packaged: 2019-10-01 19:56:41
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 17,519
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17250398
Author URL: https://archiveofourown.org/users/cadignan/pseuds/MoreThanSlightly, https://archiveofourown.org/users/verity/pseuds/verity
Summary: “Is this permanent?” Keith asks. His mom said it was a normal part of alien puberty, so he fucking hopes it’s temporary. He'd kind of like his dick back.





	1. Chapter 1

**THE TALK, PART ONE**

Keith has to talk to his mom.

Even after two years with her in the quantum abyss, there’s usually still pleasure in the thought: he has a _mom_ and he can _talk_ to her. This morning brings him no such happiness. Keith doesn’t spend a lot of time thinking about feelings, but right now he’s consumed by a sort of angry panic. He doesn’t cry easily, and he’s never cried from anger or panic before, but ten minutes ago— _before_ he had the life-saving revelation that he could ask his mom about this—he found himself wiping tears from his eyes. What the fuck.

He messages Krolia through the Garrison’s private comms system, grateful he doesn’t have to leave his room to do it.

 _Mom_ , he writes. Okay, maybe that’s still kind of special. It’s the next part that sucks. _Something is wrong with me._

She writes back _what_.

 _I think it’s a Galra thing_ , Keith clarifies. He can’t bring himself to specify the problem in words. _It’s never happened before_.

He hopes it’s a Galra thing. The alternative—that it’s just some bullshit his unique physiology decided to pull on him—is worse.

He also hopes it’s not permanent. And that it never happens again.

Someone knocks on his door. Keith doesn’t want to get out of bed. That’s rare for him. Normally he and Shiro would already have gone for a run by now. Among other things.

Shiro knocked on the door earlier this morning and Keith pretended he was still asleep. Keith can’t think about that because it inspires a dizzying array of unwanted feelings, and he’s trying not to cry again before his mom shows up.

He wishes Shiro was here. Shiro would hug him and tell him it was all going to be okay. At the same time, Keith's very, very grateful and relieved that Shiro is _not_ here, because then Shiro would look at him, and what if Shiro looked at him and didn’t want to touch him anymore?

Fuck. There go his eyes again.

Keith pulls on the loosest, bulkiest clothes he can find and goes to the door. Krolia slips in, takes one look at his face, and says, “Oh, sweetie.”

She’s never called him a pet name before. Too bad this was what it took.

“I did wonder, these past few weeks—but I wasn’t sure this would happen to you,” she says, and Keith is grateful that he doesn’t have to explain in words, but also mortified that she knows without asking. She puts a reassuring hand on his shoulder. “I smell it now, though. It’s a normal part of maturing into adulthood for Galra.”

“You mean, like… puberty?” Also, she can _smell_ that? Weird.

Krolia smiles apologetically.

This is bullshit. Keith already went through human puberty. He shouldn’t have to do it again. He crosses his arms over his chest, then winces. His chest is a different shape than it was yesterday, and it’s tender.

Come to think of it, it’s been tender for days, but he’d put it down to bruising from sparring. Of course he had. Why the fuck would he have expected to grow breasts?

That’s not the only change.

“Is this permanent?” Keith asks. She said it was a normal part of alien puberty, so he fucking hopes it’s temporary. He'd kind of like his dick back.

“No,” she says, and the relief is so overwhelming Keith nearly falls apart on the spot. Then she says, “Although if you get pregnant, your body will stay in this configuration until the pregnancy ends, one way or another.”

“If I—what?”

Keith hadn’t even considered that he might have grown a whole new set of internal organs. He _has_ felt pretty fucking tired for the past week or two, and that suddenly makes a lot more sense.

“If you’re unhappy about it, that means you’re probably already on your way to another change,” Krolia says.

Good. Except. “Changing _back_ ,” Keith says. “That’s what you mean, right? I’ve been through all the human options here.”

“Have you?” Krolia asks. “I was given to understand that there are a variety of human sexes, just as there are Galra. We have four common configurations, plus a range of—”

“Four?” Keith interrupts.

“Their names are all in Galra, but I can try to explain if you want. There’s the question of internal organs, first—two of our sexes have wombs. And there’s genitalia, and secondary sex characteristics like breasts—are you alright, sweetie? Can I hug you?”

Keith mutely accepts the hug. Krolia's gentle with him, and he tries not to ruin it by thinking _she knows my breasts are sore_. She sits on the bed next to him and says, “Keep asking questions, if you want.”

“So there might be… more changes?” he asks.

“I don’t know. Not everybody goes through all four standard configurations, but lots of people do. I did.” She smiles. “Wanted to explore my options.”

Is Krolia remembering this _fondly_? Keith doesn’t remember human puberty with anything but mortification.

“Lots of people go through one change in their youth, then go back to the body they were born with and stay there. Some people find a shape that suits them better than the one they were born with. Some people have two favorites they alternate, some change all the time. Everyone’s different. I think this kind of adaptability is why there are so many different-looking Galra. We also find it very easy to intermix with other species.”

Well, Keith knew that last bit already.

“I’ve changed a couple of times as an adult,” Krolia says. “But that was all voluntary and intentional. It’s just the first few you don’t have control over. Later on, you can do it for fun.”

“What?” Keith is tired and cranky and every stupid little feeling is making him cry. He has _tits_ and they’re so sore that they ache even when nothing is touching them. This is not fun.

“Random, involuntary changes like the one you’re experiencing don’t happen to adults—except maybe in times of great stress. But now that you have the ability, you’ll retain it. You can change when you want.”

Sure, because this is something Keith would love to go through again. He gestures vaguely at his body. “So how long will this last?”

“Like I said, if this doesn’t feel right for you, it won’t last. But changes take a few days.”

Keith sighs. Maybe he won’t have to talk to anyone about it. The changes in his body aren't obvious as long as he’s not naked. He can tough it out.

And he’ll have to avoid Shiro.

“I’ve been on Earth enough to know humans don’t always embrace what their bodies can do, but in lots of Galra cultures, this is an occasion to celebrate,” Krolia says. “I know it might not feel that way to you.”

“It doesn’t,” he confirms, a little bit sour. Keith liked his body the way it was. So did Shiro.

Krolia puts an arm around his shoulders and squeezes. “I’m glad you were willing to talk to me about this. I know most humans think of this sort of thing as private, and I haven’t always been in your life.”

“I’m glad you were here to answer my questions,” Keith says, because he is. She made him feel way, way better about this.

They sit there quietly for a minute before Krolia straightens, pulling away. “Stay right there," she says as she gets to her feet. "I know what you need."

His mom comes back a few minutes later with what must be her own compression bra, and Keith turns bright pink. He doesn’t want to blush. He’s grateful she’s respecting his wishes and being so practical about it. But _borrowing my alien mom’s bra_ wasn’t something he ever expected to do, and it’s a pretty weird feeling.

“Thanks.”

“It’s the least I can do after making you inherit all this physiology,” she jokes.

He stands up to give her a sudden, fierce hug. There’s so much more than physiology between them. “I love you,” he says. “You’re a good mom.”

Is it his imagination, or does Krolia duck her head in embarrassment? “I love you, too.”

 

* * *

 

 

His paladin armor fits more or less the same, and he’s relieved by what he sees in the mirror. If his face is different, it’s subtle. He doesn’t have to shave, at least.

Keith runs into the MFE pilots in the break room at the start of the day and manages to mutter “fine” in response to their attempts at small talk, then stalks out with his coffee while they stare at each other in silence. He counts it as a successful interaction, considering his mood.

Things go better with Pidge, who never wants to talk about feelings and who regards inhabiting a body as a necessary inconvenience, an opinion Keith is inclined to agree with right now. They just get into the Green Lion and chatter about some new improvements they might make to the cloaking tech for twenty minutes as the two of them depart for a relief mission to North Africa, stopping in Algiers, Sfax, and Tripoli.

Seated in the cockpit, communing with Black and watching the clouds pass by beneath her paws, an ease settles over Keith. He’s been carrying around a tightness in his chest since he woke up, and here in the upper atmosphere, it releases.

“Keith?”

“That sounds great, Pidge,” he says over the comms. He doesn’t know what they've been talking about for the past few minutes, but he means it. They're trustworthy.

Pidge turns on the video and an unimpressed image of their face shows up on his dashboard. “You have no idea what I said.” Not an accusation, but a flat statement of fact.

“I’m sure it was brilliant,” he says. “You good to land?”

“It’s not my attention span you need to worry about,” they say and turns off the video. The Green Lion zooms ahead of him and lands neatly in the airstrip at Houari Boumediene, where a couple dozen people are already lined up along the edge, waiting to unload their cargo.

A train of people file into and out of their cargo bays, taking out box after box of food, medicine, and fuel to deliver to the camp. This area of the coast was hit hard in the invasion, like so many others. The Paladins will be flying relief missions for a long time yet. It’s awful that so many people are living in need, but this work is fulfilling in a way that battles—even victories—never are. Keith isn't killing anyone or blowing anything up. He's helping people live.

He’s in a good mood when they leave, and an even better one when they get back into the air.

Over the comms, Pidge says, “Hey, Keith?”

“Yeah?”

“I just wanted to say… I know we don’t really… talk. About stuff.”

“Pidge,” Keith interrupts. “Are you about to ask me about my feelings?”

Their shoulders nearly touch their ears. “Uh, well, I was about to tell you that I’m _not_ going to do that, but—crap, do I have to ask you now that I brought it up?”

“I’m okay,” Keith says and for right now, it’s true. “And I would love to _not_ talk about that with you.”

“Oh, good,” Pidge says, relieved. “Can we just be not-talking-about-it friends?”

“Yes,” Keith says with equal relief. They’re perfect. How hard would it be to rearrange this week’s schedule so he can fly all his missions with Pidge and no one else? “Let’s talk about cloaking devices again, Pidge. I’ll listen this time.”

 

* * *

 

 

Fifteen minutes after Keith files a request to reschedule tomorrow’s intelligence briefing with Shiro and Kolivan in favor of flying another mission with Pidge, Shiro shows up in the doorway of the Garrison common room. Keith is still checking his messages, but he drops the datapad onto the couch cushions when Shiro shows up. Has Shiro seen the message? Did he come here to call Keith out?

The sight of Shiro leaning against the door jamb makes Keith forget his worries. Shiro’s so solid. The building might as well be leaning on him instead of the other way around. Atlas, indeed.

Kinkade’s sprawled on the other couch staring at his datapad in silence, but as soon as Shiro shows up, he darts out of the room. That happens a lot. People tend to give the two of them a wide berth. Once, Shiro had made the mistake of remarking that he wasn’t _that_ strict as an officer, so there was no reason for people to flee, and Rizavi had muttered something about “choking on fuck fumes.” Shiro hadn’t caught it and Keith hadn’t felt the need to enlighten him.

Once the room is empty, Shiro saunters in. He sits one hip on the back on the couch and looms over Keith. He says, “You wanna—” with a smile and a nod in the general direction of their rooms.

Normally Keith would be half-hard by now, just from Shiro’s closeness and the suggestion in his tone. A keen awareness prickles all over his body, the absence between his legs making him clench his muscles.

Oh. Wait. Is this what arousal feels like if you can’t get hard? Shit. It was too much to hope that his sex drive could go offline for a few days. Shiro is… Shiro, sitting there with his big, thick thighs inches from Keith’s face. Keith does want him. That hasn’t changed.

Shiro doesn’t usually have to finish this kind of invitation, but today Keith can barely string words together. "Uh… what?"

Now that Keith's noticed his body, he can’t stop. Desire pools low and hot in his belly; his nipples tighten and he has to make a conscious effort not to squirm. Fuck, has Shiro always smelled that good? Is this one of the signs Krolia mentioned? Shiro’s perfectly starched collar reveals only a sliver of bare skin beneath the hard line of his jaw. Keith wants to drag him down onto the couch and run his tongue along it.

“I was asking if you wanted to come back to my room. Or yours.” Shiro’s brows draw together slightly—just a faint fold of the skin between them. "But we don’t have to if you’re… We could do something else together.”

This is obviously uncharted territory for both of them. Keith has never _not_ been in the mood. He’s in the mood right now and he wishes he wasn’t.

“We could watch _Dolphin President_ or one of the other things the MFEs are always making references to,” Shiro says. He smiles at Keith, his frown smoothing away. Keith’s stomach flips.

"I have to, um… go… file some stuff," Keith says, and flees.

 

* * *

 

**THE TALK, PART TWO**

As sweet as it is to have an emotional moment with his mom, Keith expects her to leave after the “I love you.” He has a bra and some reassurances, he’ll survive. But Krolia stays.

“How much do you know about vulvas?” she asks. “Do you want me to draw you a diagram? Do you want instructions?”

“Mom,” Keith says, half-strangled. “I… _no_.” He will figure it out himself or die trying. Still, she’s only thinking of his happiness, and as much as he doesn’t want a vagina owner’s manual written by his mom, it’s thoughtful of her. “But thanks for offering. Also, please don’t tell anyone, Mom.”

She presses her lips together. “I won’t do anything against your wishes, Keith, but there’s one more thing we absolutely have to discuss. There’s a chance you’ll go into heat, and it could be dangerous.”

“Heat?”

“I know this probably isn’t something you want to talk about with me, but have you felt any more… urges than normal?”

“No,” he says, and then adds, “no more than normal,” and somehow doesn’t choke on it.

“That’s a good sign for now. I still think it would be best if you warned Shiro.”

Keith makes a noise of acknowledgement; he’s not interested in telling anyone about this. A moment later, he says, “What did you mean, dangerous? You mean for me?”

“Potentially, yes,” she says. “But the physical consequences for you would be minor. It’s the psychological aspects that concern me.”

Keith really, really does not want to ask this next question. “Psychological consequences?”

“You’re likely to become sexually aggressive.”

Sometimes his mom’s bluntness is welcome, and sometimes it’s really not. “Jesus.” Keith grimaces. She’d said _I think it would be best if you warned Shiro_. And Keith thought waking up with a reconfigured body was the worst of his problems. “But at least I don’t have a—”

“Do not finish that sentence,” Krolia says. “It is possible to inflict oneself on an unwilling person regardless of shape.”

“Right, right, of course, I know that, I wouldn’t—you really think there’s a chance _I_ could do that? To _Shiro_?” The thought makes him sick.

“Here is what we will do. Either you will talk to Shiro and assure yourself that he consents, or at the first sign of any urge out of the ordinary, you will tell _me_ and I will restrain you.”

“Restrain me?” Keith wonders if going into heat makes everyone _sexually aggressive_ , or if some people are more passively horny, and if so, why the hell is his mom so sure he’s one of the former? What has he done to make her think that? Why does she have any opinions on the matter at all? Ugh. Maybe she’s just preparing for the worst.

“Someone will have to. You’re strong and very skilled in physical combat. You won’t be rational.”

He sighs. “This sounds fucking awful.”

“It’s highly unlikely,” she says, squeezing him against her. “And I’m only bringing it up now so we can prevent it. You have a few days before you have to worry about the possibility of going into heat. And if it happens, well—with willing partners, it’s an enjoyable experience.”

She lets go of him and goes to the door, but before leaving, she says, “Try to think of it as less of a burden and more of a gift, if you can. It’s special. Your dad was always envious, you know. Not everyone gets to have this experience. Enjoy it.”

She shuts the door behind her, and Keith sits on the bed in puzzled silence, trying to figure out what, if anything, his mom just revealed about his parents’ sex life, and whether she just advised her grown son to masturbate.

He pulls on the sports bra and tries not to think about that or anything else.

 

* * *

 

 

The day after the change, Keith is disappointed not to wake up with an erection. He misses his dick. Normally he enjoys the first few moments of sleepy awareness, luxuriates in the pressure from the mattress, maybe rolls over and takes care of himself. He yawns, then stretches his arms up to the headboard and splays his toes as he arches his back. The firm surface of the bed feels nearly as good as usual when he rocks down against it.

There’s an idea.

His body is different, but it still belongs to him, and he can do what he wants with it. If his stupid body is going to put him through all this bullshit, it can damn well give him an orgasm. Keith has never had a partner with a vagina, and never sought out porn featuring them, but he can figure it out. It’s his own damn nervous system, after all. He ought to know what feels good.

Thus fortified, he flips over onto his back and shoves his boxers off, kicking them over the edge of the bed before he can lose his nerve. It's not like a crater opened up where his dick was—it's just his body. There's nothing to be afraid of.

The hair between Keith's legs is the same as it was a handful of days ago. He runs his fingers through it until he finds the place where his body opens up. The heat of his vulva is like the heat of his mouth, yet hotter, as if the passage leads to some molten core. Mostly, it feels squishy.  The texture is so strange and unexpected he almost withdraws his hand.

Instead, he pushes further inside. The rough pads of his fingers scrape against the walls of his vagina, hurty-good, and he pauses, confused and turned on, clenching down on himself. Everything is sort of hot and gooey; at least that's familiar. Keith pulls his fingers out, slowly, then pushes in again. Pleasurable, but not satisfying the way he expects, even after the initial squeamishness passes. It was always so obvious what he needed to do with his dick. Whatever. Keith has never backed down from a challenge. His body might have changed the rules on him, but he’s still playing to win.

Dragging his thumb against the apex, he finds—it. Oh. Inside feels good, but _this_ is amazing. He bites his lip, trying to focus and then trying not to buck up into his hand. After working himself up with exploration, getting off like this is surprisingly easy. When he comes, it's new and familiar at once—the same exhilaration of zooming right up to the edge of a cliff, the punch of the drop, the pleasure of leveling out along the wave of sensation that rolls through his whole body, leaving him shuddering in its wake.

There’s a few seconds of extreme sensitivity afterward, but it subsides quickly enough that he knows he can go again.

Keith doesn't make it to breakfast.

 

* * *

 

 

Keith misses space the most on mornings like these, when the senior brass of the Galaxy Garrison are assembled for their weekly briefing on the global relief effort led by the Paladins. First of all, there's the reports—as if Keith had written so much as a five-paragraph essay since leaving the Garrison—and then there's the hour of scrutiny by people who probably wish Keith had died in the desert or somewhere else convenient along the way. Not even jerking off for an hour beforehand could improve this meeting.

Next to him, Pidge radiates repressed energy. They hate this meeting as much as he does.

"We were able to deliver substantial supplies to all three cities," Keith says, trying to keep his voice neutral. "However, no one has fully assessed damage in the interior, especially more rural areas that relied entirely on satellites for communications. Restoring communications alone would provide substantial support to state relief efforts."

Iverson frowns.  "Do you mean to suggest that we have time or resources to manufacture _satellites_?"

"Oh, yes," Pidge says with a broad smile. "I do. Here's a list of the material resources and an approximate estimate of the time it would take Atlas to replicate—"

Keith tunes all that out. He's already read Pidge's list and talked with Allura about their trade relationships with planets in the Voltron Coalition that have substantial cadmium and titanium deposits. Voltron can't fix every broken sanitation system or gas leak on Earth, but they can relieve food shortages and give people the resources to continue the work themselves.

"We'll discuss this next week after I've had time to review your suggestions further," Iverson says, as if he can stop Keith taking up a second career in mining or Hunk from recreationally forging alloys. "Dismissed."

Out in the hall, Lance, Hunk, and Allura are waiting on the next hour of inquisition, reporting on their own relief mission. Hunk sees Pidge’s face and says, “That bad, huh?”

"I'm going to go find Matt and talk about math," Pidge says. "I need some common sense."

"Yeah, I'm gonna go hit something," Keith says.

Pidge holds their fist up for a bump.

Back in his quarters, Keith paws through his clean laundry pile and comes up empty-handed. Normally, he works out in something as close to his combat wear as possible—so, a performance shirt, skin-tight leggings, and a jock. The shirt that Shiro left here the other day will have to do. Keith ducks into Lance's room and steals a pair of basketball shorts, which hang off Keith's hips like curtains but at least camouflage his conspicuous lack of dick. Now Keith looks like a tool, but that's... fine.

This time of day, the weight room and the fitness equipment of the Garrison are sparsely populated with off-duty MFE pilots, but the rest of the gym is empty. Keith just wants a punching bag. He pulls on his gloves, warms up, and goes right in, too conscious of the small differences in how he moves. As off-balance as he felt at first, it's nothing like the awkward growth spurts he worked through as a kid.

He moves through his usual set of jabs, crosses, and squats, then settles in to work on some combinations. As soon as he starts sweating, something in him settles. He can still do this. It doesn't matter what's in—or missing from—his pants. Even if he keeps having to retie the drawstring to keep them up.

Behind him, someone clears their throat. Keith's too practiced to miss his swing. He drops his arms after, though, and turns around.

Of course, it's Shiro.

Keith crosses his arms over his chest. "Hey. Haven't seen you around today."

"You missed breakfast," Shiro says. "Sleep in?" His face shifts into something fond, an expression Keith knows so well but only recently learned to read.

"Early briefing," Keith says.

Shiro's wearing his usual gear, a loose tank and obscenely high-cut track shorts that his dick would absolutely fall right out of if he didn't have support. Keith has to reach down and grab his water bottle for emotional support. He drains half of it before he catches Shiro watching him swallow and chokes.

"You okay there?"

"Fine," Keith says, wiping water off his face with the back of his hand. He rubs his hand on Lance's shorts. "Totally fine."

Shiro is still looking at him, measuring him up. "You want to spar?"

The empty training room felt like a relief before; Keith now realizes there’s no one here to save him. "Sure," he says. "Let's hit the mat."

Even before he kicks off his sneakers, Keith knows this is a mistake. He's warmed up, but Shiro's fresh and at the top of his game. Also, all Keith wants is to be pinned to the gross vinyl mat with Shiro grinding between his thighs. Less than forty-eight hours of no sex, and he's reduced to this. He sighs and follows Shiro to the center before shifting into fighting stance.

"Haven't seen you around much," Shiro says casually as he squares off with Keith and they start moving around, darting closer to each other. "You've been busy."

Keith sidles closer. It'll be easier to take Shiro if he moves inside; at a distance, Shiro has the advantage with his longer limbs. "Missed you," he allows.

"Yeah," Shiro says, standing his ground. "Missed you in my bed." He throws the first strike.

They move back and forth across the mat, still sizing each other up. As soon as contact begins, Keith can tell that this won't be like their usual bouts, which are tests of Keith's agility versus Shiro's floating arm. Keith's off-balance, literally and figuratively, but Shiro still can't land a hit on him. "Don't go easy on me."

Shiro winces as Keith takes advantage of an opening and lands a kick to his right side. "Sorry," he says, panting. "I'm kind of… distracted."

Keith moves in before Shiro can recover and shoves him right to the floor, pinning Shiro with a bare foot on his chest. Not even the compression of his jock can hide his obvious erection. "Get yourself together," Keith says. He grimaces at how harsh his voice sounds.

Shiro doesn't look put off; he just circles Keith's ankle with his long, calloused fingers, finally getting skin to skin. Keith has to close his eyes for a moment, overwhelmed by the contact. "You have me at your mercy," Shiro says gently.

There is nothing Keith wants more—not even peace in the galaxy—than to ride Shiro's cock right on this filthy mat, where anyone could see them. Unfortunately, he can't do that without explaining this entire situation. His cunt throbs.

"I really think we should, uh—" Keith swallows. "I have to go, I'm sorry. I have to talk with Allura about—satellites."

"Those satellites, they're a big deal," Shiro says. He strokes Keith's ankle. "I get it."

It’s only a few more days like this, right? Keith can do that. Then he’ll… regrow his dick or whatever and he can go back to fucking Shiro two or three times a day every day like normal.

 

* * *

 

 

**THE TALK, PART THREE**

_Mom_ , he messages Krolia from the privacy of his room, his hair damp against the back of his neck from the cold shower he just forced himself to take. Keith needs to talk to someone who isn’t Shiro. It’s lonely, keeping secrets. _I have more questions_.

She shows up at his door a minute later. He lets her in. Krolia enters his room like she’s infiltrating a Galra base, gliding in silently. She removes something from under her jacket and plants it on his bedside table. A box.

An industrial size box of condoms.

“Uh,” Keith says. Did she forget their entire conversation? He doesn’t have a dick right now. “Not really in need of those.”

“Keep them anyway,” she says, offering no explanations. “Now, you had some questions?”

They sit side by side on the bed. Keith shifts his weight and tries very hard not to think about that giant box of condoms, or any part of his body, or Krolia, or Shiro, or anything at all. Especially not the idea that those condoms aren’t meant for him to _wear_ . They’re meant to keep him from getting pregnant. God, why did she bring so _many_?

“Do boobs hurt all the time?” he blurts, because he made her come over here and he has to say something.

“No. They’re tender when they first grow, and during certain parts of the cycle, and during pregnancy and breastfeeding. The rest of the time, they’re just there.”

Keith probably won’t experience that, but it’s a relief anyway. “Oh. Good. I was beginning to wonder if everybody with boobs was in pain all the time.”

She smiles and shakes her head. “You don’t think about your penis all the time, do you?”

“I’m not answering that,” Keith says. He’s not an expert on moms but he’s pretty sure that is not a normal mom question. He changes the subject. “You said you could smell me.”

“Yes. I forget sometimes how little humans can smell.”

“Okay,” Keith says. He’s not going to tell his mom that nothing smells different except Shiro, because he doesn’t want to know what, exactly, his mother can smell about their relationship.

That’s a weird thought. Keith goes back to his questions. “You also said there were two sexes with wombs. What’s the difference?”

“They don’t look different. One has a menstrual cycle and the other has an estrous cycle.”

Keith doesn’t know what that second thing is. “How do I know which one I currently am?”

“Right now you have a menstrual cycle,” Krolia says. “Same as me.”

Periods. Keith tries not to grimace. He’s so not prepared for that, and he hopes he'll change again before it becomes an issue. “You can choose your reproductive biology and that’s what you picked?”

She smiles and pats him on the shoulder, and too late, he realizes how rude he was. Other people can do what they want with their bodies. “Every form has its disadvantages. It’s not all bad. This is the body that made me your mother, after all.”

“Sorry.”

She squeezes him around the shoulders. “It’s okay. I know it’s a lot to take in.” Neither of his parents were in his life when Keith went through human puberty, so he never got any version of this talk. Birds, bees, the wonders of growing up, whatever. There was a mandatory sex ed class where a grouchy, overworked teacher told them to keep it all in their pants, and that was it. The whole experience was terrifying and overwhelming and lonely.

The thought fills him with gratitude for this time around, which is awkward and uncomfortable, but also kind of… sweet. She brought him a bra and condoms, and she’s trying her best to make him feel better about this whole thing.

“I’m glad you’re here,” Keith says, meaning it with every particle of his body, in ways he can hardly express.

In response, she hugs him again and kisses the side of his head.

 

* * *

 

 

In the middle of the night, or maybe very early in the morning, Keith wakes up to Shiro saying his name through the locked door of his room. His alarm hasn’t even gone off. Is something wrong? Keith stumbles to the door and opens it.

Shiro falls silent when he sees Keith, closing his open mouth and shifting his weight between his feet. That’s when Keith remembers. He glances down at his t-shirt, stretched over a pair of small but obvious breasts. His nipples are peaked. They, unlike the rest of him, are unequivocally glad to see Shiro.

“Oh,” Shiro says. Then: “Were you going to tell me about this?”

“Maybe you should come in,” Keith says, because he doesn’t want to talk about this with the door open, even if it is four-thirty AM.

The sheets on Keith's bed are still warm. Shiro sits down next to him, close but not touching. Somehow that's worse than if Shiro put a hand on Keith the way he so often does—to affirm, to reassure, and newly, to pleasure—and Keith can't help but turn his whole, yearning body toward Shiro, drawn into his gravity well. “I was going to tell you,” he says. “Eventually.”

The furrow between Shiro's eyebrows smoothes to leave his expression tellingly blank.

Keith sucks in a breath. Shit. He knew this was going to go badly, but he didn’t know how badly until right now. “You have a lot on your mind, I didn’t want to bother you—”

Shiro looks down at the rumpled sheets for a moment. “This does explain the past few weeks."

“Weeks?” Keith asks. “This happened three days ago.”

“You’ve been moody and exhausted for weeks,” Shiro says. “Remember that day I had to poke you awake in a briefing? I thought you were getting sick at first—”

“I never get sick.” Well, maybe he never got sick on Earth because all of the bacteria and viruses there are adapted to humans. He isn’t one.

“I know,” Shiro says. “You were always hungry. When Galra go through a change, it requires a lot of energy. I remembered that. Like a growth spurt, but you don’t necessarily get taller.” He says the word _change_ with emphasis, almost like it has a capital letter.

“Wait, you know about this?” So that’s why Shiro didn’t start their conversation with _what the fuck_. The knowledge throws their sparring match into a different light. It feels unfair, somehow, that he suspected this before Keith did.

“I was a Galran prisoner for a year.” Shiro sounds tired. “I learned a lot about them.”

“And you... noticed?” Keith says, trying to keep the horror out of his voice and failing. Of course Shiro noticed. They _sparred_.

“I’m sure no one else did.” Shiro's expression relaxes, mouth curving up at the corners. “I doubt anyone else around here stares at your ass as much as I do.”

Shit. Keith can't tell if he feels worse about being so exposed or about trying to keep it a secret. Krolia told him not to. He stares down into his lap.

“Only an expert would know," Shiro says gently, and then he does touch Keith—he puts his broad, warm hand on Keith's thigh. "I care about you. I pay attention."

On that very first morning, Keith had indulged in a fantasy of Shiro hugging him and telling him everything would be okay. Maybe his fantasy hadn’t been so far off the mark. Keith should give Shiro more credit—of course he’d be sympathetic about this. Who knows more about not feeling at home in their body than Shiro? Keith sighs. “I didn’t think you’d want to—be with me while I was like this, so I thought we’d just take a break for a few days until it passed.”

“Without telling me anything."

“Well, I mean… you’re not interested in having sex with women.”

“You’re not a woman,” Shiro says. “Unless something else has changed?”

“No,” Keith says, fidgeting. His long silence makes Shiro raise his eyebrows. “Sorry, I’m just… working through some stuff.”

Shiro shifts his body toward Keith, mirroring his position; his mechanical hand comes up to cup Keith's jaw. “I like your body, Keith. But I like it because it’s _you_.”

Warmth suffuses Keith, settling into his chest, pooling between his legs. So close to Shiro's hand on his thigh. “That’s good," he says hesitantly.

"I'll show you." Shiro strokes Keith's lip with his cool thumb. "If you want."

Keith swallows. "Yes," he says. "Please."

Shiro draws the hem of Keith’s t-shirt up, exposing his hip, then traces his metal index finger down the ridge. Keith trembles.

His whole body feels coiled tight like a spring. He leans into Shiro's touch, then forward, close enough to kiss. “You’re sure?”

“I love you,” Shiro says. "Keith, I want you. I want—"

Keith can't process this. He can't think about this now. "Shiro," he says, then kisses him, everything familiar and alien at once. The air feels charged with a new energy. "Yes, I—yes." He crawls into Shiro's lap, swinging his leg over Shiro's waist. Shiro wraps his arms around Keith, his hands flat against Keith’s back.  Keith rocks down onto him, already wet, and finds Shiro hard. He shivers, full-body. "Fuck."

"Yes," Shiro says, and his cheeks are dusky pink in the pale bedroom light. He grinds up again Keith. "Do it. Do me."

Keith reaches down between them and pulls Shiro out of his boxers. He has to stand for a moment to shimmy his own underwear off, and then he's on top of Shiro again, figuring out the angle to slide him in. Shiro's cock slots perfectly inside him. Keith's mouth waters. Holy shit, this is nothing like doing this on his own. The fit is tight, but the fullness makes his whole body tingly and warm, and Shiro gasps when Keith clenches around him. Keith does it again just to watch him shudder.

Then he remembers. "Shit," he says, drawing back until Shiro's dick slips out of him with a slick pop. "We need a condom."

"Oh," Shiro says, eyes wide. "Oh, yeah. That's a good idea."

Keith's never had sex with anyone but Shiro; he's never used one of these before. Shiro takes pity on Keith after a few seconds of fumbling with the package and rips it open himself, then pinches the tip and rolls the whole thing on in a practiced gesture. He hasn't gotten any less hard. Keith's mouth goes dry.

"All good now," Shiro says, too seriously, so Keith shoves him back on the bed and squirms his hips over Shiro's until Shiro is back inside him again, so deep that Keith has to draw back when Shiro bottoms out. "Fuck, Keith. Keith."

They've fucked a lot—in a lot of positions, a lot of places—but this is something else, like an out-of-body experience inside his body. Keith loses his rhythm as soon as he finds it, hips jerking unsteadily down on Shiro's while Shiro sucks at his swollen and sensitive breasts. Shiro shoves a hand between them. Keith has to show him where to touch, but it only takes a minute of Shiro's clumsy touches before he comes, shuddering and tightening around Shiro until Shiro follows, digging his fingers into Keith's hips.

Shiro turns them on their sides, after, and Keith whimpers when he pulls out. "Condom," Shiro reminds him. He's back in just a moment, curling his big body around Keith's. For a moment, Keith's nervousness returns, but then Shiro kisses his forehead and strokes the side of his breast. "Believe me now?" he says.

"Yes," Keith says. "I do."

 

* * *

 

**THE TALK, PART FOUR**

“How do you know I have a menstrual cycle, though? Can you smell that, too?”

“No,” she says, so gently he knows something bad is going to follow. “Or rather, I could smell it if I sniffed you, but I don’t need to. I know because we’re sitting here having a conversation, and you’re still able to speak in sentences.”

“So the other cycle is the one where you go into heat,” he says flatly.

“Have you talked to Shiro yet?”

“No.”

“You should,” Krolia says. Then, darkly, “You’d better.”

One thing about losing your parents early and ending up in the system is you don’t get a lot of warnings and lectures in the “no child of _mine_ would ever” vein. Nobody has a personal stake in your bad behavior. Low standards abound. Every adult in your life arrives pre-disappointed in you.

If the circumstances weren’t so unbelievably weird and horrifying, Keith might be— _very_ secretly—emotional. Krolia expects better of him. So few people ever have.

Shiro’s one of them.

Keith clears his throat. “What are the early signs? How will I know if that happens?”

“I don’t want to scare you, because it won’t necessarily happen. But you’ll know right away if it does. If you go into heat, every moment you’re not having sex will feel like dying.”

“What the fuck,” he says. “Why would evolution come up with that? How does that make any sense? And why would anyone choose it for themselves?”

“A menstrual cycle seems more manageable in comparison, doesn’t it?” Krolia says. “As for going into heat, well, it’s no fun if you’re alone. It can be dangerous, if you don’t have people watching out for you. But I don’t want to give you too much of a negative impression. It doesn’t suit the life I’ve chosen for myself, but like I said, every form has advantages and disadvantages. If you’ve got a willing friend or two, going into estrus can be great. Some people love it. There are whole communities dedicated to it, rituals, special resorts, that kind of thing.”

Keith blinks. There’s a lot to Galran culture that he missed, fighting the empire.

“Even if it doesn’t happen now, I recommend trying it at least once. Have you ever wanted to turn off your brain? It’s a memorable experience. There’s a word for it in Galran. I think in English, you say ‘bender.’”

“That’s for alcohol. It means when you get really drunk for days—oh.”

This might happen to him. He might go into heat and be brainlessly, constantly horny for days. The strangeness of the situation strikes him anew, and he breaks down laughing. It’s all too much.

She pats him on the back. “Shiro’s a good choice. He looks like he’ll hold up. You might want to have a back-up in mind, though.”

“What?” That’s all Keith ever says now. His mom coolly assessing Shiro’s sexual stamina isn’t even the weirdest part of what she just said. A back-up? Oh God. She’d said _a willing friend or two_. “No, no, there will be no back-up. I promise I’ll talk to Shiro, Mom, but I can’t expect him to participate in this. He’s busy. He doesn’t need to worry about that. I’m just gonna tough it out if it happens. It will only be a couple of days.”

“Keith. You are severely underestimating the effects,” she says.

 _But Shiro’s not—he won’t—_ Keith stops the thought and sighs in frustration. He wants to complain that this isn’t fair and he shouldn’t have to deal with it. That won’t do any good.

“You’re not… worried he won’t accept this part of you, are you?” she asks, far too perceptive.

 _Yes, Mom, that’s exactly what I’m worried about_.

“I think you should give him a chance,” Krolia says. “But if he hurts you, I know hundreds of ways to kill a man and I’m very good at covering my tracks and disposing of bodies.”

Other people’s moms would say that as a joke, he’s pretty sure. Moms are uncharted territory for him. But he does know Krolia, and she sounds frighteningly sincere.

“Not that I don’t appreciate the sentiment, but… please don’t murder Shiro, Mom.”

“Kidding, of course,” she says, with a smile and a little waver in her tone that means she was absolutely not kidding. “If you have any more questions, let me know. Make sure you’re eating and sleeping enough. Changes can really take it out of you.”

 

* * *

 

 

They lie together in the dim light of the bedroom for a sleepy, languorous stretch of time, and then Keith remembers something. “Apparently there’s a chance I’ll, uh, go into heat.”

“Mm,” Shiro says, not surprised but maybe not fully awake, either. “Yeah, I remember something about that. It’s like what happens to cats, right?”

“Yeah. With all the loss of control that implies.” Keith blushes, but then he thinks of the sex they just had. He can still feel a sweet ache between his thighs. All in all, this is going way better than expected. He twists so he and Shiro are facing each other. “If it happens, I’m gonna... fixate on you. But I know you’re busy and you probably don't want to spend two solid days trapped with me while I’m out of my mind. Krolia offered to restrain and sedate me.”

Shiro stares at him. Improbably, he breaks into a grin. “Oh my God, you’re a _sex werewolf_.”

Keith makes a face. “Can you not?”

“Okay. You’re really worried about this, huh?”

“Krolia made it sound dangerous." His throat feels tight, all of a sudden. "I hate the idea of hurting you.”

“You won’t,” Shiro says, immediately and with far more certainty than Keith can muster. “Even if you’re out of your mind with lust, you’ll still be _you_.”

There’s a bitter note in that sentence. Keith reaches for Shiro’s hand and gives it a squeeze.

“So what exactly did your mom say?”

Keith sighs. “Krolia said it’s like turning your brain off. She also said I’m likely to be ‘sexually aggressive’ and then acted like she was gonna have to fight me to get me away from you.”

“Keith,” Shiro says. Keith braces himself. _We have a whole planet to rebuild. People rely on me. I can’t take days off work to tend to your peculiar sexual needs_. “She’s not going to have to fight you.”

“I don’t know, she sounded pretty—”

“Keith. If your mom tries to stop us from having outrageous alien werewolf sex, I will fight _her_. When does it start?”

“Can we not call it—” Keith stops mid-sentence. Shiro wants to. _Shiro wants to_. He can call it whatever he damn well pleases. “Uh. I don’t know. It might not happen at all. I don’t think it’s the type of thing we can schedule.”

Shiro hums, then leans in and rubs the tip of his nose against Keith’s. “Well. I’ll be ready.”


	2. Chapter 2

Nothing his mom said could possibly have conveyed the all-consuming physical and mental sensation of going into heat.

Keith expected to feel… extra horny, or something. And it’s not that he doesn’t feel that, but there’s no ramp up. It doesn’t so much creep up on him as punch him in the face.

It’s 7:58am and Keith is already seated at the long conference table in the briefing room. He smells Shiro walk in the door before he sees him, which, _whoa_. That’s all the warning he gets, because as soon as he turns and lays eye on Shiro—that amiable good-morning smile, the breadth of his chest in that uniform—a fire of lust sweeps through his whole body, and the only thing Keith knows for sure is that if Shiro doesn’t fuck him right now, he’s going to _die_.

“Uh. You okay?” Lance prods him in the side. He whispers, “You were fine and then Shiro walked in and all of a sudden—well, not to make this weird or anything, but you look like you wanna eat him alive.”

“Yeah, not that we’re not happy for you two, but maybe dial it back for the meeting?” Hunk suggests.

“I don’t think he’s listening, guys,” Pidge says, and they're right because Keith only comprehends the words long moments after they were spoken, as though he’s floating in the darkness, far enough from the Castle of Lions that his comms system is delivering more bursts of static than intelligible audio. They wave a hand in front of his face and he bats their hand away so they're not blocking his view of Shiro.

He can’t be expected to hear anything, not when his body is so loud. His nipples are hard points against the constricting fabric of the compression bra. All of his clothes feel too tight. He’s agonizingly aware of the emptiness where Shiro ought to be.

He has to fix this. He pushes away from the table and crosses the room. Shiro is talking to Sam Holt and Coran. They can wait. Keith can’t. His brain is a scream and his body’s on fire.

Someone grabs Keith around the waist tight enough to lift his feet off the ground a little. Fuck that. Keith kicks both legs forward into a pike, planning to flip them both onto their backs with the momentum. His captor leans forward and forces him to plant his feet on the ground, not letting go. In addition the arm around his waist, there’s another around his chest, trapping his arms against his side.

Mmph. Keith struggles, but… the touch makes his brain quiet down. It’s nice to be held. The person behind him is big and solid and warm. Oh. It’s Hunk. Not as good as Shiro, but Keith lays his head back and stops moving. He can feel the heat of Hunk’s body in a line up his back.

“Hey-hey,” Hunk says cheerfully over Keith’s shoulder. “Hi there, Coran, Sam, Shiro. No need to look over here. I was just giving my friend Keith a good morning hug, like I always do.”

Into Keith’s ear, he says, “Call me crazy, but it looked like you were about to jump Shiro in the middle of the briefing room, in front of Pidge’s dad and Coran, who’s like, practically our uncle by now. And that doesn’t seem like your usual style. You wanna step outside and tell me what’s up?”

It would take _so many words_ to do that. And they’d be farther away from Shiro. That’s the opposite of what Keith wants. “No.”

“Guess I should have expected that,” Hunk says. “Also, not to make this any more awkward, but you’re, uh… pretty into this hug. Is it a hug if I’m just holding you captive so you won’t attack Shiro, since I’m still convinced that’s what you want to do? We’ll call it a hug. Either way, didn’t expect you to lean into it so hard. Also, we’re touching a lot and there are some things I didn’t know about you.”

Oh. He can feel Keith’s breasts.

“You don’t have to say anything, it’s cool, it’s cool, I won’t mention it again, sorry I brought it up, none of my business—”

“Galra puberty,” Keith mutters. Thinking of the words and getting them out requires an extraordinary effort. Why isn’t Shiro touching him? Why isn’t Shiro’s dick buried deep inside him? No. Don’t say that out loud. You’re talking to Hunk. “It’s temporary.”

“Oh. Ohhh. Shit, that’s intense. Are you okay? Do you need anything?”

“Shiro,” Keith says, a breathy whine. Dimly, he’s aware that he’d be embarrassed about how needy that sounded, if he still cared about dignity. He’d be embarrassed by leaning back into Hunk’s touch and prowling after Shiro in public and telling Hunk about the changes, too. The thought escapes him like a tool slipping out of his hand in zero G. He watches it float out of reach.

Dignity is for people who aren’t _fucking dying_.

“I can do that for you. In fact, I think it would be a huge relief to both of us.” Much louder, Hunk says, “Hey, Shiro, I have a question—can you come over here? Like, right now?”

Keith takes Shiro's glance like a spear through his body. Thank fuck, he rushes over. Hunk shoves Keith into Shiro’s arms.

Mmm. It was nice to touch Hunk, but it’s glorious to touch Shiro. Blissful. Heavenly. Or it would be, if Shiro were fucking him.

“So that’s… some kind of situation there,” Hunk is saying to Shiro, “and I think you’re the best qualified to address it, and I know I don’t really have the authority to do this, but I move we cancel this meeting.”

If Keith rises up on tiptoes, he can lick the side of Shiro’s neck above the collar of his uniform. And if he sidles over a few inches, he can slot one of Shiro’s beautiful thick thighs between his own, and then they’ll really be getting somewhere.

Keith barely touches his tongue to Shiro’s skin before Shiro yelps, “Okay. Uh. Apologies, everyone. This meeting is postponed. Please—” mm, Keith put that there, that little hitch in Shiro’s breath, “—remain calm and return to your stations. Further instructions to follow.”

There’s chatter and movement around them as people disperse. Shiro grabs Keith by the wrists before Keith can get his belt undone. “Keith.”

Keith isn’t in the mood for talking, but Shiro can say his name like that, pitched low and urgent, any time.

“This is your heat,” Shiro says. It isn’t a question. “I promise I will get you what you need, but you have to keep it together right now. Clothes on—mine and yours. No touching. Just until we get out of here. We’re going to your room.”

No touching? “I can’t,” Keith says, with what feels like the last gasp of his rational mind.

“Okay,” Shiro says, like it’s just one more fact and not evidence of Keith crumbling into desperate ashes right in front of him. He’s always so calm under pressure. He can think his way out of anything. Shiro is going to fix this. Keith is going insane or dying or possibly both, but he believes that.

Shiro takes him gently by the elbow and they take a couple of steps like that, but it’s too tempting. Keith has the freedom to plaster himself to Shiro’s side and run his hand down the front of Shiro’s body, and he takes it. It’s good. Better than good. Keith wants more. More touching, less clothing.

“Wow, okay, you really have no impulse control,” Shiro is saying. Has he been talking this whole time? He pushes Keith away. They tussle, and that’s _yes_ , his brain and his whole body say _yes_ , Keith would like more of that, but Shiro stops them before they get anywhere good.

Except now he’s marching Keith out of the room, both wrists held behind his back, and that has promise. Keith wishes they were touching more. He tries to back up so he can wriggle his ass against Shiro’s cock, but Shiro holds him at arm’s length.

He’s talking. People talk _so much_. There are so many words. It’s exhausting. But Shiro is talking right next to Keith’s ear in his beautiful deep voice, and he can keep doing that. Sometimes he says Keith’s name.

Keith’s room is a long way away. Shiro said they could fuck once they got there, and it’s important to give Shiro what he wants, but they can get there faster than this glacially slow walking pace. It’s not enough to walk there. It’s not enough that Shiro is only holding him by the wrists. Keith needs more.

It feels like it’s been a hundred years, but if Keith thinks about it, it’s probably only been a minute. Still, he thinks—he can feel the gears grinding in his head—a minute of compliance is long enough to get Shiro to relax his grip and drop his guard. Shiro feels confident he’s handled things. That makes him vulnerable.

Keith snaps Shiro’s hold on his arms and whirls to face him. Keith dives, shoving his free arm between Shiro’s thighs and pulling Shiro’s body across his own. Shiro is shocked, judging from whatever he’s saying, but when Keith stands up, hoisting Shiro over his shoulders, Shiro doesn’t struggle. He curls around Keith, his head hanging down, and shakes with laughter.

That’s… good? Cooperation is good. The sound and sensation of Shiro’s laughter makes him dizzy with want. Shiro is heavy over his shoulder, his ass and thighs right next to Keith’s face, and the urge to lean in and rub his face on Shiro’s body like a cat is too strong. He gives in. Then he tightens his hold on Shiro and sprints the rest of the way to his room.

 

* * *

 

 

Keith opens the door with one hand, kicks it shut behind him, and deposits Shiro carefully in his bed. That’s the last bit of delicacy he possesses. He shucks off his pants and underwear, shoves Shiro's clothes down his thighs, and straddles him. Then he plunges Shiro's cock deep into the liquid heat of his cunt.

It’s so good, it’s so good, it’s _so good_ that Keith can pause at the end of that first stroke and exhale with relief.

“Hey,” Shiro says. “Not that I’m not loving this, but I need you to reach into my jacket pocket and pass me the piece of paper you find, okay?”

Keith extracts a stiff, perforated piece of paper from Shiro’s jacket and gives it to him. Shiro gently tears along the dotted lines until he’s holding a small square on his index finger. “Your mom gave this to me—they’re formulated specifically for going into heat. Stick your tongue out.”

Oh. It’s a contraceptive.

When Keith doesn’t immediately comply, Shiro says, “Please?”

Keith feels a strange, instinctive resistance. His body is seized with a wild kind of wanting he’s never experienced and can’t put words to, not just an objection to the contraceptive but a desire for something more. _Come inside me. Fill me up. Get me pregnant_.

But that desire, as strong as it is, has nothing on the one that’s been running his life for years. Protect Shiro. Keep him safe. Make him happy. Keith can’t bear the thought of Shiro wanting something from him and not getting it, so he opens his mouth and lets Shiro press the tab of paper to his tongue.

With Shiro’s finger right there, Keith can’t help but close his lips around it. Shiro inside him—it’s _almost_ what he wants.

“Good,” Shiro says, running his metal fingers under Keith’s jaw, making sure Keith keeps his mouth closed until the tab dissolves. Keith does, because Shiro wants him to, but he trembles while he waits through it. “You’re okay.”

Keith is not okay. He is burning up with need and something worse. The head of Shiro's dick keeps sliding against Keith's labia and Keith has to wait, he said he'd wait.

Shiro slides his finger out of Keith’s mouth and kisses him. Keith wastes no time lifting his hips, impaling himself on Shiro. _At last_. This is the only thing that feels good: being full, being filled. The swell of Shiro's cock inside him. Nothing else matters.

Shiro reaches up and strokes his cheek. “I hate to see you in distress, but I’m not gonna lie, the look on your face when you slid down just now did a lot for my ego.”

Just sitting on Shiro isn't enough to sate Keith for long. He pushes himself up and slams back down, each movement so heady with sensation that he feels dizzy. Shiro's words eventually filter into Keith’s brain, and he files them away as _good: Shiro is happy_.

Keith doesn't notice that Shiro has undone the clasps on both their uniform tops until he tries to push Keith’s jacket off his shoulders. Okay. Shiro wants their clothes off, and he can have that. Still moving his hips, Keith tugs down one sleeve, then the other, then dumps his jacket on the floor. His tank top and bra follow. Something flutters at the back of his mind, a dim memory of being self-conscious about his chest, but Keith has more pressing concerns now.

Shiro reaches up as if to touch him, but Keith grabs his still-clothed wrist and forces it down.

“Bossy,” Shiro says, smiling.

It’s too hard to get Shiro out of his uniform, trapped beneath Keith as he is; Keith leaves him with his collar loose, the white cotton of his undershirt rucked up his chest.. There’s nothing to be done about the pants Keith shoved halfway down his legs, not while they’re fucking—Shiro’s not going anywhere, and Keith takes savage satisfaction in that. Spread out, dishevelled, and flushed, Shiro is delicious to behold.

Keith leans down to kiss him, fierce and hard and demanding, and Shiro gives him everything he asks for. His hair is thick and soft against Keith’s fingers, almost too short to grip. Keith goes for it anyway, cupping Shiro’s head and not letting go.

They kiss until neither of them can breathe, and Shiro is still gasping when Keith sinks his teeth into the side of his neck and sucks, drinking in the taste of Shiro’s skin. Shiro chokes out a wordless groan. Keith drags his tongue over the tender spot he’s just bitten and then kisses his way down to Shiro’s pecs, clenching around Shiro every time he gets a reaction.

“I’m not gonna last much longer if you keep that up. Can I touch you?” Shiro is breathless and amused. Teasing. He says something else, and the words filter through eventually: “That bite mark is definitely going to show while I’m in uniform, by the way, and you can claim you were out of your mind and didn’t know that, but I won’t believe you.”

Keith wants to say something in response to that, but his brain is a riot of needs and sensations, so when he lifts his head, what he comes up with is a worried, uncertain, “Bad?”

“No,” Shiro says. “Not bad. Good, actually. You can do it again if you want.”

Keith bares his teeth in a smile. Then he pulls Shiro’s prosthetic toward his pussy. Shiro laughs, says, “Alright,” and dips his fingers between Keith's thighs to his clit.

Pleasure spikes through him at Shiro's touch and Keith falls forward with the shock. He closes his eyes. It’s so much. Intense in a different way than the fucking. He shudders, grinding against Shiro’s cupped fingers. His hand spasms and clenches in Shiro’s hair.

Shiro runs his other hand from Keith’s hip up his side, warm and quick, a gesture of pure affection. When Keith opens his eyes and meets Shiro’s gaze, Shiro slides his hand back down and settles it on Keith’s ass.

Something about that encouragement lights a fire under him, and Keith drives himself down harder and faster than before, until there is only the hot, slick friction in him, on him. Keith pulls Shiro up by his hair and kisses him. Shiro moans into his mouth, and his hips jerk upward once, twice, and then he’s coming. Keith follows him over the edge, his orgasm a white-hot burst of relief.

Shiro collapses back against the bed and Keith slumps over him, his cheek plastered to Shiro’s collarbone, brushing against the flap of Shiro's uniform jacket. As the sensation ebbs, he regains some clarity.

“Thanks,” he murmurs, not lifting his head. “That was… intense.”

“It was great,” Shiro says. At last, Keith shifts off him, pressing himself against Shiro’s side, and Shiro takes the opportunity to kick off his pants. He almost stands up, but then Keith’s hand locks around his bicep.

“Uh. Sorry. I’m better, but I’m not… you can’t go anywhere.”

“Not even ten feet across the room to stretch while you have eyes on my naked ass the whole time?” Shiro asks.

Keith should be able to laugh about that, but he can’t seem to unclench his hand. The idea of Shiro leaving is… no. He can’t. That can’t happen. “Sorry?” he offers. If he focuses, he can see the red mark he left on Shiro’s neck, just under his jaw, and his face heats. “And sorry for biting you.”

“Don’t be sorry. I meant what I said. It was good. You can do it again if you want.”

“The heat… it makes me feel like an animal,” Keith says. “Even now, I’m barely managing. This could end at any second.”

Shiro twists so they’re lying front to front. He runs a finger down the length of Keith’s nose and then under his chin, lifting until they’re eye to eye. “You’re my favorite animal.”

Keith rolls his eyes, but he can already feel his pulse picking up. Shiro’s smile does that to him.

“I won’t pretend to know what you’re going through, but… that sex kind of made me feel like an animal, too,” Shiro says. “It was great. Freeing. Although I wouldn’t mind if we took it slower next time.”

“Mm,” Keith says. He presses his nose into Shiro’s neck, nuzzling the bite mark. Shiro smells good.

“You’re kidding.” Shiro pulls away, but it's only to finally shrug out of his jacket and take off his undershirt. The undershirt ruffles his already-messy hair as he draws it over his head. “Keith, it hasn’t even been five minutes.”

“You smiled at me,” Keith murmurs, half-heartedly defensive. His interest in talking is waning already. He rubs his body along Shiro’s.

“I _smiled_ at you,” Shiro says, incredulous. The laugh he produces is a soft vibration, one that makes Keith lean in and nip at his neck again. When Shiro puts a hand in his hair, Keith closes his eyes and tips his head into the warmth of the touch, wanting more. The pressure of Shiro’s fingers against his scalp almost renders him boneless, except for the persistent need between his thighs.

“I was not prepared for this to be so adorable,” Shiro says, mostly to himself. Keith is busy reaching between them for Shiro’s softening cock. “Sorry. Not seventeen anymore. Or Galra. I need a minute.”

Keith reaches over the end of the bed and rummages in the bedside table until he finds lube. Then he slides down Shiro’s body, parts Shiro's legs, and settles himself between them. He squirms, his sex clenching around nothing, then reaches back into the drawer. Yes, there's something for him, too.

As he slides the toy inside him—thick, purple, the finest that the Spencers' in the Spacemall had to offer—Keith takes in the view, which is one worth savoring. His mouth grows as wet as his cunt, looking at Shiro’s thick, lightly furred thighs giving way to the thatch of dark hair around his dick. All that power, at rest. All these hidden places, displayed. He reaches forward, his fingers slick with lube, and stops when Shiro speaks.

“I’m not objecting, but you do realize that isn’t going to give you relief, right?”

Keith draws his brows together in consternation and holds very still. He catches Shiro’s eye and glances at his hand, fingers hovering at the entrance to Shiro’s body. “Yes or no?”

Shiro laughs—what’s funny?—and says a few things that are neither yes nor no, then, at last, “Yes. Yes please.”

Shiro’s going to let Keith in. What a gift. The ache between his own legs edges toward pain as the dildo slips loose, and he shoves it back inside himself with his heel, hissing at the renewed pressure as he braces himself against his foot to keep it inside. Keith stretches forward to trace a circle with the tip of his finger over the delicate whorl of skin. Shiro relaxes at his touch, and as Keith opens him up, he releases happy sighs. Keith loves those sounds. Shiro’s quiet and it draws Keith in, making him forget everything but the next hum, the next whimper, the next shudder.

He slides another finger in, careful and slow, and grinds down onto the toy inside him while he does it. Shiro writhes against his hand, his body flushed all over, a sheen of sweat on his skin that Keith wants to lick off. Even with this much intimacy, he craves more. Shiro’s dick is filling again and the sight lets loose a slippery rush of desire in Keith. He fidgets, shifting his weight, and even through the drowsy sweep of his lashes, Shiro notices.

“Hey, I have an idea,” he says, which Keith ignores, and then, “Spread your legs,” which Keith understands with such a bolt of clarity that he knocks his knee against Shiro’s thigh in his haste to follow instructions. The dildo slides right out as Keith moves, and for a moment, he clenches miserably around nothing. But it’s easy for Shiro to reach him with the new prosthetic—even easier for him to slip one thick metal finger into Keith, and then another. Even two are bigger than the toy at its widest.

Keith exhales. “Fuck.” The cool fullness soothes the ache he’s been ignoring all this time, but it’s not enough. He leans forward, urging Shiro to move deeper and harder. That puts his face so close to Shiro’s dick—now beautifully, deliciously hard—that there’s only one thing to be done. Keith plants a sloppy wet kiss at the root and then licks his way up to the tip, still working his fingers inside.

“Holy shit,” Shiro says, and Keith knows a _yes_ when he hears one. He lifts his head to grin at Shiro, whose eyes are feverish and whose hair is a wild white halo around his head, and then drops back down. “Keith, I’m close.”

Keith rocks his hips against Shiro’s hand. He’s close, too, the urgency of the heat making him slick and swollen and ready. Shiro crooks his fingers, rubbing up against him just right, and Keith echoes the action, sliding his fingers in and out of Shiro. Shiro’s panting now, only a stroke or two away from coming. Keith fits his lips over the head of Shiro’s cock and slides it into his mouth. Shiro weaves his left hand into Keith’s hair and grasps hard when Keith swipes his tongue over the slit. The hot spurt of Shiro’s orgasm in his mouth is all it takes for Keith to come apart. A moment later, he’s resting his head on Shiro’s stomach, still shivering from the force of it.

Shiro pulls him close after a while and it’s a relief to stretch his legs to their full length. He murmurs something into Keith’s hair, and with great effort, Keith deciphers the sound as “Wow.”

“Mm,” he agrees, borderline delirious from how good Shiro’s skin smells. After some groping around in the haze of his brain, he remembers the word he wants. “Again?”

Beneath him, Shiro shakes with desperate laughter.

 

* * *

 

 

“Keith. Please. It is two in the morning and we have been fucking since eight AM. I’m only human. I need to sleep.”

Keith gathers all his wits to make sense of that and when the meaning coalesces, he frowns. “I can’t.”

“Can’t sleep or can’t stop? Or both?” Lying next to him, Shiro gives him a searching look, his heavy brows drawn together in concern. His eyes are huge and dark.

He’s so pretty. Keith wants to kiss him. No. Think. Shiro wants something; you have to give it to him. Keith grabs Shiro’s metal wrist and draws his hand down. Shiro tucks two thick metal fingers inside Keith and settles against him. Keith clenches down on them, helpless. Then he pulls Shiro until his head is pillowed on Keith’s chest. It hurts a little, but it’s a good kind of hurt. “You sleep.”

“With my hand here?”

“Mmhmm.”

“You’ll be okay?”

“Yes.” It’s not true yet. Keith will make it true.

Shiro yawns and resettles his head on Keith’s chest. Keith strokes his hair until he falls asleep, burning with the effort of holding still so Shiro can rest. Shiro needs to sleep and Keith has to let him. They’re touching, and Shiro is inside him, and that can be enough for now. They’re still fucking, it’s just a very, very slow kind of fucking. The next stroke won’t come for hours. Until then, Shiro is draped over him, warm and heavy and breathing evenly, and that soothes something inside him that has nothing to do with the heat. Shiro is happy. Everything else can wait.

 

* * *

 

 

Keith surfaces while Shiro is holding a bottle of water to his lips and tipping his head. _Shit_. He sits up straight and tries to grab it from Shiro’s hands, only to discover that his wrists—and his ankles—are tied to the bed frame.

He swallows the water that’s in his mouth, moves his head to stop drinking, and feels his face flush a dull red.

Shiro raises his eyebrows. “Non-stop fucking for two days and it’s the water that makes you blush?”

“Fuck off.” The reminder of his helplessness embarrasses him, and he turns his face away.

“Oh good, you’re back,” Shiro says with genuine relief.

He’s sitting on the bed, as naked as Keith is. His hair is a wreck and he’s sweaty, but the smile he gives Keith is big and bright. Shiro usually reserves that kind of smile for victories and long-delayed reunions… _oh_.

“The last few times I said anything to you, it didn’t result in conversation.”

Shit. Keith is gonna have to strap in for further embarrassing revelations. Wait, he's already strapped in. “Why am I tied up?”

Shiro unties the rope around one arm, then rubs the tender skin of Keith’s wrist with his thumb, dropping a kiss to it. “What do you remember?” he asks, untying the remaining ropes with methodical care.

The past forty-eight hours are an orgasmic blur. Keith’s whole body is tender, and his abs and thighs feel like he spent too many hours on the training deck. “Uh.” Keith smiles but can’t look directly at Shiro. A rush of shyness comes over him. He’s not normally shy, but he’s also never spent two solid days as a sex-crazed animal. All the reservations and inhibitions he couldn’t feel during the heat are back full-force. “I had a good time.” His brain plays a highlight reel of licking and sucking and fucking, and the sheer quantity of it—plus the creative inventory of positions—is astounding. “I think you had a good time, too.”

Shiro laughs. “Yeah. The in-heat version of you was very invested in me getting off, too. Maybe a little too invested. I had to leave a couple of times and you, uh, followed me. I didn’t think you’d be thrilled to learn we had public sex once you were back to normal, so I took some precautions.”

The ropes.

A memory hits him and Keith flops back against his pillow and covers his face. “We fought in the hallway outside the bathroom. Oh God, I put you flat on your back and almost ripped your clothes off.” He peeks through his fingers for confirmation and Shiro is laughing again.

“I think Pidge really regretted choosing that moment to walk by,” he says. “You’re a hell of an opponent even when you’re in heat.”

Pidge was in the hallway?

He closes his eyes. He’d straddled Shiro and pinned him to the floor, grinding into him while he tried to pull off Shiro’s t-shirt. Wait. Shiro had been wearing clothes.

“Was I naked?” Keith asks, already knowing the answer. Shit. “Pidge saw me naked.”

“I don’t think they saw that much,” Shiro says. “You were so fast I didn’t even see you until you were on me. Pidge was passing by and they yelled ’no.’ I assume they ran into the bathroom because I heard the door slam, but by that point, I wasn’t looking at them. But you were easy to distract, so I won that round. I got us back in the room behind closed doors, and that was a lot of fun.”

Keith touches one of his shoulder blades and his fingertips find a bruise. He smiles to himself, and when he looks up, Shiro is smiling, too.

“I’m not sure you did win that round,” Keith says. “I think I won that round at least twice.”

“I’m amazed you can keep score,” Shiro says. “I counted somewhere in the neighborhood of sixty-eight, but I was distracted a fair amount of the time, and I couldn’t always tell where one stopped and the next started, so the data’s not perfect. Anyway, after the briefing room and the hallway, I figured out the rope.”

 _Sixty-eight_. Well. That certainly is a number. In Keith’s memory, it feels more like… one. A very long one.

The briefing room? Oh. Keith does have a memory of being singularly focused on getting one of Shiro’s thighs between his own. There might have been other people around. “Sorry.”

“You don’t have anything to apologize for,” Shiro says. “But your mom delivered a care package and I am accepting expressions of sympathy for _that_.”

“A care package?” Keith glances around his room, which he’s been in for two days but hasn’t really seen, and notices a box on the floor. It’s easy to see because his room is otherwise bare. But Shiro’s naked in his bed, and that’s decoration enough.

He shakes his head to clear his thoughts. “I don’t think I’m quite done yet.”

Shiro exhales. “Damn.”

Keith gives the box another look. He sees energy drinks, snacks, and… that’s a bottle of lube. Okay. “Do I want to know what else was in the care package? Oh, fuck, she brought you the rope. Oh, that’s weird. Sorry. For what it’s worth, I think all of this is a lot more standard for Galra?”

“Yeah, she mentioned that. And she did bring the rope, among other things.”

_Keith, I can’t possibly go another round right now. I have to rest._

_Shiro, I need it. Shiro, please. Please please please Shiro please._

Wow. Had he really said that out loud? In that tone? Apparently he had. He remembers a feeling of crushing desperation, watching Shiro stand up from the bed and walk a few steps away, and then unspeakable elation when Shiro turned around and came back to bed. He had something in his hand. A dildo with a bulge at the base that's the size of Keith's fist.

_Your mom said I wouldn’t be able to keep up with you, and I guess she was right. You’re not listening. Sometimes I’m honestly not sure you understand words. I guess I don’t have to talk dirty. You know her exact words were ‘you think you can take it and that you don’t need help, but he’s going to wring you out like a wet rag’? Then she put the box in my hands and left. At the time I was insulted, but I can’t lie, I’m pretty goddamn grateful right now._

“Oh,” Keith says. He hadn’t heard much of that at the time, and he’s not sure he welcomes the clarity now. “So my mom… wow. My sympathies.”

Shiro shrugs. “It was embarrassing, but she was right about everything. She sent some information to my datapad, too. That’s how I know it’s ‘unusual’ and ‘a sign of profound emotional connection’ that not only did you remember my name and _only_ want me while you were in heat, but you also cared a lot about whether I got off. Not that you needed to worry on that count.”

Keith’s face is just a permanent blush now. “Well,” he says. “I hope that’s not a surprise.”

“It’s not. Still nice to get confirmation, though.” Shiro bumps his nose against Keith’s. “You were very sweet.”

“Thanks for seeing me through that,” Keith says. He takes a deep breath and looks heavenward. He really, really should not want sex right now, and yet. “I hate to ask you for more, but if you keep sitting in my bed and touching me and flattering me—”

“What, you think I can’t go again?” Shiro teases. “It’s pretty sexy to get to have a conversation with you. It was great for my ego when all you wanted to say was _harder, Shiro_ , but I like this better.”

Keith smirks. “These big, long, hard sentences really doing it for you?”

“Oh, baby.”

“Is there anything you want?” Keith asks. “My memory’s all sort of soft-focus, but I think we did pretty much everything—”

“Talk to me,” Shiro says. “I wasn’t joking about the sentences.”

“Like… dirty talk?”

“You were pretty good at that even in your heat haze,” Shiro says. “Did you know the Galra have a specific word for it? The info was all translated, but there was a footnote about it. The literal translation is ‘lust stupidity,’ but I thought ‘heat haze’ sounded nicer.”

“Thanks for sparing my feelings,” Keith says dryly. “When did you have time to read footnotes?”

And then he remembers being tied up and fucking himself on that dildo while Shiro sat in a chair across the room and ignored him.

“I see you remember,” Shiro says.

“I’ve never been into that whole… ropes and power exchange thing,” Keith says. He’s just shifting his weight in the bed. He’s not _squirming_. And he could make eye contact with Shiro if he wanted to. He’s just taking a moment to observe his own feet. Oh boy. Shiro deserves to know the end of the sentence. “But that’s kind of a hot memory.”

“Honestly, I wasn’t trying to do any kind of power exchange,” Shiro says. “I needed a break. That was the only way to take one without making you suffer.”

“Wow,” Keith says.

“Don’t even think about apologizing,” Shiro says. “Although, if you ever want to do this again, I’d appreciate some warning so I can plan the op.”

“I can’t believe you just referred to me falling into a mindless frenzy of animal lust as an ‘op,’” Keith says. “No, wait, I absolutely can. But you don’t have to worry. For now, I’m happy to have sex with you in my right mind. My right body is another question.”

“It’s all the right body, Keith,” Shiro says and kisses him. “And I always approach sex as a tactician. That’s why I’m so good at it.”

“Uh huh,” Keith says. “It was real tactical when I swept your legs and put you on the hallway floor. I hope this is the kind of talking you were dreaming of.”

“It is exactly what I was dreaming of,” Shiro says. He bends down to press a kiss to Keith’s lips. Keith’s legs are spread, and Shiro dips a finger into him. Keith shivers. He’s already silky wet. “And you know taking a couple of hits in a fight isn’t the same as losing.”

“Oh, are we keeping score now?” Keith leans back, wanting to change position so Shiro can fuck him, and then yelps and reaches behind himself. “Did something happen to my ass? Do I have a bruise?”

“Um.” Shiro is blushing. “It’s, uh, more of a bite mark.”

Keith bursts out laughing. He doesn’t remember that particular episode. “So I was the lust-addled animal-brained one and somehow _you_ bit _me_?”

“You bit me first! And it was hot. And then things just… escalated.”

“Shiro. Stand up.”

Shiro slips his finger out of Keith and gets to his feet. Now that Keith is looking, he sees little marks all over Shiro’s skin, especially concentrated around his neck, shoulders, and upper arm. Well. Keith can’t fault himself for that.

“Turn around.”

Yes, there they are, two or three prominent red marks right at the thickest part of Shiro’s ass. His inner thighs are peppered with marks, too. Keith brushes his fingers across a few of them, presses into a mark high up on Shiro’s thigh, and Shiro shivers. Keith puts his hands on Shiro’s hips and spins him back around, then spreads his legs and falls flat to his back. Shiro takes the cue and slides his cock into Keith, who raises his hips until he can wrap his legs around Shiro’s waist.

“So you like biting,” Keith says.

“The past couple of days have proved that I like almost anything, as long as it’s with you.” Shiro sets a steady pace with his thrusts. Keith doesn’t mind. He hasn’t been fully present for two days, and now that he’s here, he wants to prolong the moment.

“Me too,” Keith says. “You know. In case there’s any other secret desires you’d like to reveal.”

Shiro blushes again, which means he absolutely has something to say, but he makes Keith wait for it. Keith tightens his grip on Shiro’s waist, moves his hips in time with Shiro’s thrusts, and slides a finger down over his clit. Shiro pants as they pick up the pace, then reaches down and interlaces one of his hands with Keith’s.

“I love fucking you,” he says.

“Uh huh,” Keith says, because he’s still waiting. “But…?”

“I miss getting fucked,” Shiro says. “I mean, _nothing_ against this, you’re perfect, I’m happy, but maybe next time we could—”

“Shiro.” That’s his heart’s desire? The thing that’s making him blush? Adorable. Keith levers himself up and pulls Shiro down into a kiss. Then, for good measure, he bites Shiro’s earlobe. “I will fuck you until you see stars.”

Shiro comes inside him right then, and Keith follows an instant later.

 

* * *

 

 

A couple days later, Keith is lying on a couch in one of the Garrison common rooms, petting Kosmo while his mom reads something on her tablet across the room, when Lance, Hunk, and Pidge wander in.

“Keith!” Lance says. “Nice to see you back in the world.”

Keith gives the three of them a lackluster wave. What are they going to say? If Shiro were here, they’d all shut the hell up.

“One of the cadets told me you picked Shiro up in a fireman carry outside the briefing room,” Lance says. “Is that true? I bet it was hilarious.”

Christ, were there witnesses to everything? “It’s none of your business.”

“Oh, don’t be like that! You got us out of two days’ worth of meetings with your sex shenanigans, Keith, you’re basically my hero. I just want details.”

“And I don’t want to give you any,” Keith says.

“That cadet was exaggerating,” his mom says, a cool interjection from across the room that surprises all of them. “You can check the surveillance footage if you don’t believe me.”

Keith freezes. What is she doing? His memory of the heat isn’t perfectly reliable, but he did hoist Shiro over his shoulder and drag him back to the room. That cadet was telling the truth.

Lance perks up at Krolia’s suggestion. “Any chance you can find it, Pidge?”

Pidge groans. “I saw things with my own eyes that I can never un-see, Lance. Don’t make me go looking for more.”

“Aww, c’mon, please? I’ll take all your dishwashing shifts for a week.”

“A month.”

“Done,” Lance says. “Hunk, you in?”

“I’ll pass, thanks,” Hunk says, because he’s a good friend who Keith might even spontaneously hug some day.

“So this was like… 8:15am the morning our briefing got canceled, right?”

“Huh,” Pidge says after a few minutes of contemplative staring at their screen. “That’s weird. I found the timestamps, but that footage shows people calmly filing out of the room and then… nothing. Empty hallway for the next half-hour. Shiro and Keith never show up.”

“What, no,” Lance says. “I wanted to see it! There’s another way out of that room, right? Check the other cameras.”

“There’s nothing on any of them. Face it, Keith was sneaky enough to pull a vanishing act even when he was out of his mind. You totally still have to do my dishwashing shifts, by the way,” Pidge says, smirking. Hunk declares himself neutral in the ensuing argument, which lasts several minutes.

Keith catches his mother’s eye from across the room, and she gives him a perfectly neutral expression in return. No shrug. No wink. No smile.

And yet somehow she knew he’d look at her at that exact moment.

He grins and ducks his head. A lot of things about having a badass alien super spy for a mom really sucked, like how she wasn’t there for his entire childhood and how he’d had to go through puberty _twice_ , but right now, he feels pretty good about it.

 

* * *

 

 

Over the next week, Keith’s body slowly reshapes itself. Shiro stays in his bed all the way through it, so he’s there when Keith wakes up with his first hard-on in days.

Keith grins into his pillow and then, bleary with sleep, rubs up against Shiro. He goes slow, luxuriating in the sensation, his cock against Shiro’s warm, smooth skin. From the change in Shiro’s breathing, he wakes up as soon as Keith moves behind him, but he’s content and undemanding, pressing back into Keith with a satisfied sigh.

“Hey,” Shiro says after a moment. “Was it always that big?”

Pulling back for a moment, Keith glances down. It looks big, but he’s gotten used to seeing nothing down there. His benchmarks for comparison are all fucked up. “Dunno.” He thrusts against the cleft of Shiro’s ass and then sinks his teeth into the place where Shiro’s neck meets his shoulder, which makes Shiro yelp. “Why don’t you look at it up close and tell me?” he says, licking his lips, the faint taste of salt from Shiro’s skin lingering there.

Shiro twists in his arms and his eyes go wide.

Keith is tired of freaking out. “What?” he says, flat. “Something wrong with my face?”

“No,” Shiro says, immediate and earnest. He reaches for Keith’s ear. running his fingers over the curve—no, the _point_ of it. It’s sensitive. Keith shivers. “You look a little different, that’s all. Still cute, though.”

Shiro kisses him before Keith can demand further detail, and then they’re grinding again, face to face this time, and nothing else matters. Every time Keith moves his hips, the head of his cock catches on Shiro’s, and it lights up his whole body with pleasure. He missed this. Keith sucks Shiro’s bottom lip, and Shiro gasps.

“Careful, those are sharp,” Shiro says.

Keith runs his tongue over his teeth. Oh. Sharper teeth, pointed ears—he must look a lot more Galra than usual. Shiro traces the shape of Keith’s left ear, and it derails all his thoughts; he closes his eyes and leans into the touch.

“You promised to fuck me,” Shiro reminds him.

At the thought, Keith can't help from letting out an approving rumble. "I'm going to," he says. "Where’s that legendary patience of yours?"

Shiro dips his head to bite at Keith's chin, which is so unexpected and unexpectedly hot that Keith can't resist a full body shudder, and fuck, Shiro is _still petting his ear_. This is not weirder than the morning he woke up with a vagina—and wow, that's his grounds for comparison now—but it is fucking weird. If he was going to become even more Galra, shouldn't that have happened before?

"I want it," Shiro sighs out, leaving the last word barely a whisper. "Your knot."

"My what," Keith says.

Shiro reaches down and takes him in hand, and oh, his dick is bigger now, isn't it, and there's a bulge at the base that wasn't there before. His knot. Not as big, yet, as the one on the dildo he'd used during his heat, but he flushes as soon as he thinks about getting it inside Shiro.

"You know how it works, right?"

Keith has talked about sex more in the last month than he ever wanted to in his entire life. "I think I can figure it out."

He knocks over the bottle of lube in his haste to get it out of the drawer, then spills it all over his hand when he fumbles the cap open. They might need this much lube. Shiro kisses Keith properly when Keith reaches down between Shiro's thighs to work some inside him, then slicks himself up and wipes his messy hand on the sheets when he's done. Shiro rolls Keith onto his back right into the smeared lube, too eager to care, and lines Keith up, sheathing Keith inside him in a single move.

"Holy shit," Keith whispers.

Sex with Shiro is never going to get old, even if Keith sticks to the same equipment forever. At first, he can't even tell the difference between this and his usual model. His whole focus is on Shiro, who is hot and tight and relentless as he fucks himself on Keith, the soft daze of sleep gone entirely. Keith arches up into him and closes his eyes for a moment. He feels so much more comfortable like this, swept up not in novelty but in familiar pleasure, and then in that moment, just as he feels the muscles in his thighs grow taut and his balls tighten, his dick does—something.

Shiro lets out an incredible noise that Keith has never heard before and clenches around him, holding him in. "Yes," he says. "Yes, do it. Tie me."

 _What the fuck_ , Keith thinks, and then his dick does it for him.

His orgasm feels it's happening in slow motion, like a fight scene in a movie. His breath comes out in low punches and he trembles as the sensation runs through him. Shiro comes in quick splatters over Keith's stomach, his body clenching around Keith. That sets Keith off again, and fuck, he didn't even know it was possible to come like this, just from that pressure around the base of his cock.

When Keith comes out of it, Shiro is still sitting astride him, wiping his thumb over at Keith's lower lip. "You hurt yourself," he says softly, meeting Keith's eyes.

His mouth does taste kind of like blood. That's right—fangs. "Oh," he mumbles.

Shiro just shakes his head. He strokes Keith's side gently with his other hand. "Holy fuck. That was… transcendent. I think I might have had a vision. And _you_ came for five minutes."

"I didn't know that was a thing." Keith yawns. They've only just woken up, but he needs a nap; orgasming for five minutes apparently really takes it out of you. He squirms back, trying to get out from under Shiro, only to find himself… stuck.

"Your knot has to go down," Shiro says gently, in a tone of voice that suggests he's trying not to laugh.

Keith is just going to take his word for that. “Sorry?” he ventures, and Shiro does laugh then. “Hope you didn’t have plans.”

“This _is_ the plan,” Shiro says, bending down to kiss him. Then he carefully shifts their connected bodies so they’re lying on their sides. He runs his fingers over the curve of Keith’s cheek and then back into the locks of hair behind Keith’s ears, tenderly brushing his fingertips along the sensitive lobe of Keith's ear. Keith grabs Shiro and pulls him closer. He rests his cheek against Shiro’s collarbone, inhaling their mingled scents.

“You’re good to me.”

“Yeah,” Shiro says. “This has all been selfless altruism on my part.”

“I didn’t mean the sex,” Keith clarifies, pulling back until he can meet Shiro’s gaze. “Or I did, but I meant everything else, too.”

“Good,” Shiro says. “Because it’s my plan to be stuck to you long after your knot goes down.”

" _Shiro._ " Keith's cheeks warm. They’ve never talked about this explicitly. Before they saved the Earth, the future existed in immediate, limited terms: missions, battles, vargas, dobashes. Not years. Not lifetimes. "Yes," he says. "I want that, too.”


	3. Chapter 3

Keith doesn't even notice the final time until he gets up in the night to take a piss and his dick's a little lighter in his hand. Oh. Hey. It's his dick. Nice.

He pees.

Shiro's dead asleep after a long day of red tape and trying to seem respectable to cadets, so Keith climbs right into bed beside him and spoons up against his back, tucking his knees behind Shiro's and his dick against the curve of Shiro's ass. His dick! He smiles, wraps his arm around Shiro's waist, and falls straight into an unusually dreamless sleep.

 

* * *

 

In the morning, Keith wakes up when Shiro reaches over to hit snooze on the alarm. In the light streaming from his shoulder, his hair is mussed from sleep; he has a pillow crease along his cheek. Keith pats his arm. "Shiro. Shiro." He yawns. "Guess what."

Shiro yawns in answer, then rolls over to face him. "After the last few weeks, I'm afraid to."

Keith rolls his eyes, grabs Shiro's hand, and puts it right on his cock.

"Hello there, old friend," Shiro says, stroking the length of it first with the tips of his fingers, than the backs of his knuckles. His prosthetic is always strangely body-warm. "Haven't seen you around in a while."

"Too long," Keith says fervently.

Shiro nudges Keith onto his back. "Yeah," he says—sleepy, breathy. "Let me—" He takes Keith into his mouth, waking him all the way up.

They haven't done this since everything started—even when Keith got his other dick. Shiro takes him all the way down, impossibly deep, and Keith can't breathe for a moment. Holy shit. He fights the urge to thrust, twisting his hands in the sheets. There's no way he's going to last.

Shiro pulls off for a moment, wiping his mouth. "You can do it. Fuck my mouth. I want you to."

"What," Keith says blearily.

"I liked the other equipment fine," Shiro says, patting Keith's inner thigh, then digging in with his thumb when muscle jumps under his hand. "But I missed this version."

Keith has had a lot of orgasms in the past two weeks—ones that made him feel like his whole body was flickering alive like an old fluorescent bulb, ones that burned like a fever, and ones that swamped him like a turning tide. This one starts out hot behind his hips and finishes right down Shiro's throat, liquid, heady, familiar. He slumps back into the sheets, exhausted, relieved, and finally content.

The alarm goes off again and Shiro's arm floats away to slap it quiet. "Keith." His voice is so rough, fuck. "I think we should go back to sleep."

"Uh huh," Keith says, dazed.

Yeah... he missed his dick.

 

* * *

 

 

Krolia waves him over to where she's sitting in the paladins' common area when Keith comes in to scrounge for a late lunch that afternoon. She has an empty plate in front of her, scraped clean except for a few traces of what appears to be chocolate frosting. "I see you’ve returned to your original state."

"Mom," Keith says, glancing around. Thankfully, there's no one else in the room to take note of his mom commenting on his penis. "You _see_?"

"A figure of speech," Krolia says in a tone that she probably intends to be reassuring. "I'm sure no one else can smell it on you. Get yourself something to eat."

Maybe the novelty of his mom telling him to do things will wear off someday, but today it's enough to calm him while he makes a peanut butter and jelly sandwich. All those years in space eating Altean food goo and every kind of alien cuisine, and Keith still reverts back to this whenever he's required to prepare food for himself. It's just good. It's what he knows he likes. He sets his plate on the table opposite Krolia's and busies himself taking a bite.

"Keith." His mom's face is carefully neutral. "How are you feeling?"

Keith recognizes the opening for what it is; fortunately, peanut butter takes a while to swallow. "I like this. This body, the way I am."

As soon as he says the words, Keith feels how true they are. It's a surprise bigger than all of the rest of what's happened since he woke up with a vagina. No matter how long he spends with Krolia or the Blades, he's always aware of how different he is from the rest of them. Keith's always been the different, difficult one in any group. Most of his life, he didn't know why.

This isn't like the other revelations that have swept through his life, though. He hasn't had to muddle through everything on his own; no one's shamed or rejected him. His mom and Shiro have taken care of him. They love him, no matter how he's shaped.

Oh.

Krolia reaches over and pats his hand, the one that's resting on the table, not holding a triangle of PB&J. "Congratulations," she says. "And if you ever change your mind—just think about it at bedtime. It’s up to you now."

 

* * *

 

 

Shiro insists they change Keith's sheets _again_. They washed them after the heat—even Keith could agree they were rank by that point—and it's only been a week, so this isn’t really necessary. Keith never changed the sheets at his shack. But Shiro treats remaking the bed like he’s about to leave for an all-expenses paid vacation, and every time he slides under the freshly washed top sheet, he sighs happily. Laundry is a small price to pay for that.

Keith tucks a corner of the fitted sheet under the mattress while Shiro does the same on the other end, and then something occurs to him. Shiro hasn't slept in his own bed in a while.

They pull the fitted sheet flat together and Keith says, “Do you want to do this on purpose?”

“What? Laundry?” Shiro’s face scrunches in confusion.

“No,” Keith says. “I know you started sleeping in here during the heat, because it was kind of an emergency—”

“We’ve survived a lot of emergencies,” Shiro says. “That’s the only one I’d ever voluntarily go through again.”

Keith drops his corner of the top sheet and it flutters to the mattress. He picks it up, his fingers curling absently in the soft, worn fabric. Every time Shiro is cheerful and positive about all the weirdness they’ve been through—and he always is—Keith feels delicate, transparent, like something’s about to bloom out of him. Keith risks a glance at Shiro, his white head bent as he carefully smoothes the top edge of the sheet, and wonders if he’s going to spend the rest of his life bursting with love at every mundane gesture and dumb joke.

He hopes so.

When Keith inhales, the room smells like fresh laundry and the two of them. “I don't mind washing the sheets every week. We might want a bigger bed, though.”

“We might." Shiro has little wrinkles at the corners of his eyes when he smiles now. Keith is never going to get tired of seeing them.

There's one other thing that's still eating at him, though. Keith takes a deep breath. "And you'd really— _voluntarily_?"

"Well," Shiro says in a very reasonable tone. "We didn't try everything, did we? I didn't even get to, ah. Use my mouth."

Keith flushes. He can almost imagine what that would feel like, and the thought makes him want to clench muscles he doesn’t currently have. “I guess there are still a few things left for us to try.”

Shiro comes to his end of the bed and takes his hand. He runs his thumb over Keith’s knuckles. “There’s a lifetime’s worth of stuff left to try. Sure, we’ve done it in this bed, but that was today, or yesterday, or three weeks ago. Who’s to say what it’ll be like tomorrow or the day after that?”

Keith laughs, lifts his free hand to Shiro’s face, and strokes his thumb over the scar and up toward Shiro’s eye crinkles. Someday he’ll have those, too, if he’s lucky.

“You’re right,” he says, pressing a kiss to the corner of Shiro’s mouth. “I can’t wait to find out.”

**Author's Note:**

> You can find us both on twitter: [@_cadignan](http://twitter.com/_cadignan) (MoreThanSlightly) and [@regretsonmain](http://twitter.com/regretsonmain) (verity).


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